That's because Synodontis cats (most of them) just like Pictus are schooling catfish that prefer to be in groups of at least a few individuals. Housed individually all they do is hide 90% of the time.
I'd have to disagree, I'd say most synodontis cats are rather aggressive especially to their own kind. Upside down cats are best in shoals... And I can recall one other but can't think of the name. My eupterus never hides, always with it's belly against a surface, filter intake, drift wood etc but never out of sight.
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